A Novel Allelic Variant of OsAGPL2 Influences Rice Eating and Cooking Quality

Area of Science:

• Plant genetics
• Molecular biology
• Agricultural science

Background:

• Starch biosynthesis is essential for rice endosperm development and quality.
• ADP-glucose pyrophosphorylase (AGPase) is a key enzyme in starch synthesis.
• Understanding gene function is critical for improving crop traits.

Purpose of the Study:

• To identify the genetic basis of a white-core endosperm mutant in rice.
• To investigate the role of OsAGPL2 in starch biosynthesis and rice quality.
• To explore the potential of OsAGPL2 variations for marker-assisted breeding.

Main Methods:

• Chemical mutagenesis (MNU) to create mutants in japonica rice (Nipponbare).
• Gene sequencing and analysis of the mutated OsAGPL2 allele.
• Biochemical assays to measure ADP-glucose pyrophosphorylase activity.
• Haplotype analysis of OsAGPL2 in diverse rice resources.

Main Results:

• A stable white-core endosperm mutant (h5) was generated, caused by a mutation in OsAGPL2.
• The mutation impaired starch synthesis, reducing amylose content (AC) and gel consistency (GC).
• Reduced AGPase activity was observed in the mutant.
• Specific SNPs in the 5'UTR and 3'UTR of OsAGPL2 were associated with variations in AC and GC.

Conclusions:

• OsAGPL2 plays a critical role in rice starch biosynthesis and eating/cooking quality.
• Identified SNPs and superior haplotypes of OsAGPL2 can be used for molecular markers.
• This research provides a foundation for enhancing rice quality through breeding programs targeting OsAGPL2.